1. Field of the Invention
The present invention generally relates to devices for interconnecting optical fibers, and more particularly to a device for terminating at least one optical fiber used as a telecommunications line (voice, data, video, etc.) at an active optical device, such as a photodetector or solid-state light source.
2. Description of the Prior Art
Optical fibers have replaced copper wire as the preferred medium for carrying telecommunications signals. As with copper wire, it is necessary to provide for the interconnection of optical fibers, during installation, repair or replacement of the fibers, and to terminate the fibers onto active optical devices. Optical devices include, for example, optical sensors (photoelectric diodes) and light sources (LED's, laser diodes). The termination of an optical fiber may be indirect, i.e., the fiber may be connected to some other (passive) optical device such as a beam splitter or polarizer, before the light beam is directed to the active optical device. The present invention is generally directed to a receptacle for a termination of an optical fiber.
In the fiber optic connector described in U.S. Pat. No. 5,381,498, the connector has a plug and a receptacle, the plug having a fiber-receiving, V-shaped groove for each fiber to be interconnected, with the end of the fiber terminating in the middle of the groove. The receptacle has a plate which retracts as the plug is inserted, whereby another fiber is lowered into the V-groove of the plug. Upon full insertion of the plug, the two fibers ends are in contact, and the fiber secured to the receptacle is elastically deformed to maintain a continuous compressive load between the terminal ends of the fibers. The connector provides for the quick disconnection and reconnection of a plurality of optical fiber pairs, without the use of ferrules or other alignment members. High strength fiber may be used to withstand repeated insertions and bowing of the fibers. The exact lengths of fibers (i.e., the relative locations of their terminal ends in the plug and receptacle) are not critical since tolerance is provided by the slack taken up in the bowed receptacle fiber (the terminal portion of the fiber secured to the plug does not bow, but always remains straight). The ends of the fibers may be prepared by simply cleaving and beveling; the end faces may optionally be cleaved at an angle (i.e., non-orthogonal to the fiber axis) to reduce signal reflections.
Many fiber optic splices employ plate elements having fiber-receiving grooves, with means for clamping the terminal ends of the fibers in a common groove. Some of these devices are designed to interconnect a plurality of pairs of fibers, such as the splice shown in U.S. Pat. No. 5,151,964. In U.S. Pat. No. 4,028,162, fibers approach alignment grooves at a glancing angle and are held temporarily while a connector plate is adhered to the interconnected fibers. For other examples of techniques involving bowed fibers entering alignment grooves, see U.S. Pat. Nos. 4,077,702, 4,148,559 and 5,080,461, and French Patent Application No. 2,660,442. Some of the connector designs using the principle of bowing a fiber into a fiber-alignment groove are rather complex and require many parts, such as the designs seen in U.S. Pat. Nos. 4,045,121, 4,218,1133 and 4,767,180. In U.S. Pat. No. 4,322,127, an alignment plate holds a fiber in a groove of a mold while a cast is made about the fiber. The solidified plug can then be removed from the mold.
The connector in the '498 patent makes use of the fiber bowing principle, but suffers certain other disadvantages. For example, the plug design allows dust to easily settle on the tips of the fibers, since these tips are exposed above the fiber-receiving grooves. Fibers in the receptacle may similarly become contaminated since there is no door or other means to close off the opening when the plug is not present. While the '498 connector has fewer parts than most ferrule connectors, it would still be preferable to eliminate the moving parts, such as the sliding plate and spring inside the receptacle. That design also recommends the use of high-strength fibers in the socket, making it less compatible with an embedded base of standard fiber. This patent, as with several others above, does not explain how the device might be used for termination. It would, therefore, be desirable and advantageous to devise an active device receptacle which similarly provides for the quick disconnection and retermination of one or more optical fibers, and which is simple to install and use, but further overcomes the foregoing limitations without sacrificing performance or cost.